Extensible support for vertically adjustable tables and the like



Nov. 16, 1954 H. s. MoRRow 2,694,612

EXTENSIBLE SUPPORT FOR VERTICALLY ADJUSTABLE, TABLES AND THE LIKE Filed Dec. 1l, 1952 2 Sheets-Sheet l Nov. 16, 1954 H. s. MoRRow 2,694,612

EXTENSIBLE SUPPORT FOR VERTICALLY ADJUSTABLE TABLES AND'THE LIKE Filed Dec. 11, 1952 2 Sheets-Sheet 2 United States Patent O EXTENSIBLE SUPPORT FOR VERTICALLY ADJUSTABLE TABLES AND THE LIKE Harry S. Morrow, Muskegon, Mich., assignor to E. H. Sheldon & Co., Muskegon, Mich., a corporation of Michigan Application December 11, 1952, Serial No. 325,305

3 Claims. (Cl. S11- 39) The present invention relates to vertically adjustable desks, laboratory tables, and the like, and is directed specifically to an extensible support structure for supporting a table-like work platform selectively in raised and lowered positions.

One object of the invention is to provide a novel work platform support of the above character which, as an incident to progression of the supported platform into raised position, is automatically retained in extended position by a plurality of laterally dispersed extension locks whose direct action is capable at once of positively sustaining the weight of the platform and its load, and assuring stabilization of the platform without undue stress on the supporting structure. A related object is to provide a support of this type in which the dispersed extension locks are simultaneously disengaged by a simple control movement of a single manual control member to release the support for retraction to lowered position.

In conjunction with the above objects, a further object is to provide a platform support which is automatically locked in either extended or retracted position, and manually released by a single movement of a compound control for shifting movement from either position. An allied object is to provide a platform support which is readily shiftable between lowered and raised positions by nominal control forces.

Other objects and advantages will be perceived from the following description of the exemplary embodiment of the invention shown in the drawings, in which Fig. 1 is a vertical end view of a classroom table embodying the exemplary form of the invention, the table being shown in vertically extended position;

Fig. 2 is a fragmentary vertical sectional view, taken along line 2 2 of Fig. l;

Fig. 3 is a fragmentary horizontal sectional view taken along line 3--3 of Fig. l, and including a phantom outline of upper portions of the table;

Fig. 4 is a vertical end view similar to Fig. l, but showing the table in lowered position;

Fig. 5 is a fragmentary vertical sectional View taken along line 5-5 of Fig. 4; and

Fig. 6 is a fragmentary horizontal sectional view taken generally along line 6-6 of Fig. 4.

Although certain worth-while advantages are realized from the specific correlation of structural elements forming the illustrated embodiment of the invention, it will be understood that the invention is not limited to the precise form shown, but embraces all equivalent constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring in greater detail to the drawings, the form of the invention delineated for purposes of illustration, is incorporated into a vertically adjustable classroom table 10 comprising a stationary support frame 11 surrnounted in this instance by a flat horizontal work platform 12. As the construction of one end of the table 10 is a mirror image of that at the other end, only one end is shown in the drawings.

Although the stationary framing at opposite ends of the table 10 may be of any suitable design, the present construction includes two vertical corner or side stiles 14 spanned at the top and bottom by two horizontal cross rails 15 tenoned to the stiles. A vertical intermediate stile 16 extends between medial portions of the cross rails 15 to complete the framing proper. Suitable panels 17 close the spaces between the stiles 14, 16 and the cross rails 15 For the convenience of the user, the work platform 12 is selectively positioned in either a raised or extended position above the support frame 11, Fig. l, or a lowered or retracted position, Fig. 4, in which the platform preferably rests directly on the frame. Vertical shifting movement of the platform 12 between its raised and lowered positions is confined to a translatory path by a pair of vertically elongated guides 19, 20 at each end of the table. These guides also provide lateral stability to the platform in both of its working positions.

In the preferred construction shown, the coacting pair of guides 19, 20 at each end of the table 10 includes a vertically elongated tongue (also denoted by numeral 19) fixed at its upper end to the underside of the platform 12 (in this instance through the intermedium of a transverse block 21 attached to the platform, Fig. 5) and extending downwardly over the outer face of the intermediate stile 16 of the adjacent stationary framing. The tongue 19 is contined for vertical sliding movement along the intermediate stile by the coacting guide 20 formed by the stile itself together with vertical strips 22 and gib plates 24 attached to the stile and closely engaging opposite marginal edges of the tongue.

It is helpful at this point to visualize the table 10 as being composed of two sections, a stationary section 25 comprising the table frame 11 and structural elements attached directly thereto, and a shiftable section 26 comprising the platform 12 and attached vertically movable parts.

The vertical guides 19, 20 at each end of the table 10 constitute a component part of extensible platform supports 27 at the respective ends of the table for positioning the shiftable table section in either lowered or raised position relative to the stationary section. The improved support structure provided for this purpose is designed to act automatically, as an incident to progression of the platform 12 into raised position, to retain the shiftable table section in extended position by the positive action of a plurality of laterally dispersed extension locks 29 which directly sustain and vertically stabilize the platform and any load placed thereon.

Structurally, each extension lock 29 employed in supporting the platform 12 in raised position comprises a vertically swingable elongated stanchion 30 pivoted to one of the table sections and biased toward vertical position to interlock with the other table section as an incident to lifting of the shiftable table section. 1

In the present instance, a swingable stanchion 30 is pivoted at one end 31 to the outer face of each of the corner stiles 14 of the table support frame'll. As shown in Figs. 1, 3, and 4, spacer blocks 32 are interposed between the pivoted erids 31 of the stanchions and the respective supporting stiles to dispose the stanchions outwardly of the vertical guide elements 19, 20 on the intermediate stile 16. Support studs 34 fixed to the upper end of each stanchion 30 form component elements of the latter to extend outwardly from the stationary framing 11 to underliela generally horizontal support member comprising a transverse cross rail 35 fixed to theunderside of the platform 12 and laterally abutting the transverse block 21. Tension springs 36 interconnected between the stationary framing 11 and the swingable stanchions 30 urge the latter toward upright positions to press thl support studs 34 against the underside of the platform ra' 35.

When the platform 12 is in lowered position, the low lying rail 35 holds the stanchions 30 in generally horizontal disengaged positions projecting inwardly from their respective supports. However, upon lifting of the platform 12 into raised position, Fig. l, the rising rail 35 permits the stanchions 30 to sweep into vertical positions in which they act directly through the support studs 34 and the rail 35 positively to support the respective corners of the platform 12 overlying the framing stiles 14. Thus, not only do the stanchions 30 provide a positive vertical support to the raised platform, but their wide lateral dispersion also affords a high degree of vertical stability to the platform.

To release the platform 12 for lowering movement, the extension locks 29 formed by the stanchions 30 are all simultaneously disengaged by a single manual control member 37. As shown, this member constitutes a rotatable control shaft 39-'runninglongitudinally' under the middle of the platform 12 and fitted at each end with a manual rotating knob handle 40. Each end of the shaft 39 piercesy the adjacentA guidertongue..19 and platform rail and is journaled in a bearing block 41 xed to the underside of the platform 12 outward of the. adjacent rail. A takeup device 42.1ixedV toy the shaft 39 between each platform rail 35 and the adjacent guide tongue 19 is interconnected with theY two. proximate locking stanchions 30 to tip the latter inwardly and out of elfective supporting relation to the platform 12 in response to manual rotation of the shaft (clockwise in Fig. 1).

Structurally,v the preferred takeup device 42 comprises a sheave 44 havingrtwo pull cords 45 fixed to the periphery thereof. and extending to the adjacent stanchions 30. Itshould be. noted in passing that the pull cords 45 also. serve to limit the upward swinging movement of the stanchions 30 once they have reached locking position after raising of theplatform 12.

Clearance for downward movement of the control shaft 39 as an incident` toI lowering of the platform 12 is provided by slotting 46 the upper cross rail 15 of the support frame 11, Fig. l.

The platform 12 upon reaching its lowered position is automatically locked in thisr position by a detent 47 including a radially extending hook 49 fixed to the takeup sheave 44, Figs. 1, 2, and 6. After tripping of the support stanchions 30, which creates slack in the pull cords 45, the hook 49 is free to swing under the action of gravity into a depending position, Fig. 4. As the platform 12 approaches the support frame 11, the beveled extreme end 50 of the hook 49 rides to one side of a coacting retaining pin 51 projecting outwardly from a horizontal bridge 50 spanning the two gib plates 24. Just as the platform 12 cornes to rest on the support frame 11, a frame supported spring 54 engaged by downward movement of the hook 49 snaps the latter back into vertical position to engage the lip 55 of the hook under the retaining pin 51, thus locking the platform to the frame.

A simple turning of the small knob 40 used to release the platform 12 for downward movement (but this time in the opposite direction) is all that is necessary to disengage the detent hook 49 and free the platform for upward shifting movement.

Actual raising and lowering of the table platform 12, once it has been released from a working position, is effected manually. However, the weight of the shiftable section of the table, which includes the platform 12, is counterbalanced by tension spring means having a low spring constant which enablesv the shifting movement to be carried through by a nominal external force. In the illustrated construction, two springs 56 are used. In order that the spring constants of the springs may be kept low, even though the two springs are approximately strong enough to support the shiftable table section, the springs are made quite long. Then to accommodate the length of the springs they are trained respectively over two pulleys 57 mounted on opposite edges of the intermediate stile 16 near the level of the supports for the stanchions 30. Opposite ends of the respective springs are attached to the lower end of the guide tongue 19 and to the adjacent ones oftheside stiles l14.

I claim:

1. Vertically adjustableplatformr means of the character described comprising, in combination, a support frame, a vertically shiftable platform disposed generally above said frame, vertical vguide means interconnecting said frame and said platform, a support rail attached to the underside of said platform, vertically swingable extension stanchions pivoted to said frame at opposite ends of said rail, biasing springs connected to said stanchions to urge the latter upwardly into engagement with said rail, said stanchions serving to automatically lock said platform in raised position as an incident to progression of the platform into said position to support and vertically stabilize the platform, and a manual control for simultaneously releasing said stanchions and including a control shaft journaled underneath said platform and having a control handle on one end thereof, and takeup means fixed to said shaft and interconnected with said stanchions for tripping the latter in response to rotary movement of said shaft.

2. In a vertically adjustable work platform assembly, the combination of a stationary section including a support frame, a vertically shiftable section including a work platform, vertical guide means interconnecting said sections, a plurality of horizontally dispersed extension locks on one of said sections biased to lock said shiftable section in raised position and positively support andy vertically stabilize said platform, compound release means connected to said extension locks to disengage the latter simultaneously for releasing said shiftable section for downward movement, coacting detent means on said two sections for automatically locking said platform in lowered position, and said detent means being interconnected with said compound release means to be controllably disengaged thereby to free said shiftable section for upward movement.

3. Vertically adjustable table means comprising, in combination, av stationary support frame, a vertically elongated guide on said frame, a work platform disposed generally above` said frame, a guide tongue fixed to said platform and depending downwardly into guided relation to said frame guide, a pulley journaled on said frame adjacent said guide thereon, a long counterbalancing spring having a low spring constant trained over said pulley and attached at opposite ends to said guide tongue and said frame, a plurality of horizontally dispersed extension'locks mounted onvsaid frame and biased to automatically lock and vertically stabilize said platform in raised position, a compound manual release interconnected with said locks for simultaneously disengaging the latter, a detent for automatically locking said 'platform in lowered position, and said detent being connected-to said compound release for disengagement thereby,

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 862,791 Bawden et al. Aug. 6, 1907 1,372,626 Michaels Mar. 22, 1921 1,606,485 Smouse -c Nov. 9, 1926 1,714,244 Rowley May 21 1'929 FOREIGN PATENTS Number Country Date 10,783 Great Britain 1915 

